<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  
  <title>Document</title>

  <style>
    #box{
      width: 1500px;
      height: 500px;
      /* background-color: lightskyblue; */
      font-size: 2em;
      background-color: aqua;
    }
  </style>
</head>
<body>
  <div id="box" value="111">
1
  </div>
  <div id="aaa">
aaa
  </div>
  <span id="myinput" value="22">
2
  </span>
  <input type="text" id="myinput">
  

  <!-- <script src="./demo.js"></script> -->
  <script>
    let a = document.getElementById('box')
    // console.log(a);
    a.onclick = function(){
      console.log(aaa);
    }
    console.log(box.value);
    
  </script>
</body>
</html>